- Track-Type Tractor:
- D3G (S/N: CFC1-UP; CFF1-UP; JMH1-UP; BYR1-UP)
- D4G (S/N: FDC1-UP; HYD1-UP; CFN1-UP; TLX1-UP)
- D5G (S/N: WGB1-UP; RKG1-UP; FDH1-UP; FDW1-UP)
- D4G (S/N: FDC1-UP; HYD1-UP; CFN1-UP; TLX1-UP)
Introduction
This Special Instruction outlines the procedure to rework the mainframe on the machines that are listed above. The rework procedure extends the service life of the mainframe.
Do not perform any of the procedures until you have read the information in this publication.
Also refer to the appropriate Parts Manual, Operation and Maintenance Manual, Disassembly and Assembly Manual and Service Manual.
Welding Requirements
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Personal injury or death can result from fumes, gases and ultraviolet rays from the weld arc. Welding can cause fumes, burn skin and produce ultraviolet rays. Keep your head out of the fumes. Use ventilation, exhaust at the arc, or both, to keep fumes and gases from your breathing area. Wear eye, ear and body protection before working. Protect yourself and others; read and understand this warning. Fumes and gases can be dangerous to your health. Ultraviolet rays from the weld arc can injure eyes and burn skin. Electric shock can cause death. Read and understand the manufacturer's instructions and your employer's safety practices. Do not touch live electrical parts. See "American National Standard Z49.1, Safety in Welding and Cutting" published by the American Welding Society. American Welding Society2501 N.W. 7th Street Miami, Florida 33125 See "OSHA Safety and Health Standards, 29 CFR 1910", available from U.S. Department of Labor. U.S. Department of LaborWashington, D.C. 20210 |
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Refer to the Special Instruction, REHS1841, "General Welding Procedures".
Welding quality is critical to the success of the reinforcement procedures. Welds must be smooth and continuous. No overlap is allowed. Grind the ends of the welds to a smooth radius.
If the vertical position is the only possibility, the welding must be done in the vertical up position.
Penetration characteristics may vary greatly depending on the electrode diameter, shielding gas, welding current, and plate thickness. Geometry of welded joints, surface conditions, and composition of the base metal and electrode also affect welds.
When welding, use mild steel low hydrogen filler metals excluding (SMAW welding electrodes). Controlled heating cycles may be required to control micro-structure zones that are affected by heat. These electrodes are used on hardened steels and steels with a low alloy in locations that an undermatched weld deposit is allowed or preferred.
The basic welding wire must be the equivalent of one of the following: AWS A5.18 ER70S, ER70S-3, ER70S-6, ER70C-6M, AWS A5.20 E70T-1, E70T-5, E71T-1 and AWS A5.17 F7AEM-12K, F7A2-EM13K.
All welds shall be free of welding spatter or slag in order to avoid issues with assembly and contamination.
All electrodes must be completely dried. The electrodes can be dried by heating the electrodes to 300°C (572°F). The electrodes must be dried for at least 30 minutes.
Do not weld in windy conditions. Do not weld when temperatures are below 16°C (60°F).
A root pass may be required before certain welds are finished.
General Outline for Repairing Mainframe
- Inspect the frame for cracks.
- Check the right and left side behind the front hardbar. Refer to Illustrations 1 and 2.
- Check the right and left side under the cab. Refer to Illustrations 3 and 4.
- Repair the cracks.
- Close up the current crack in order to allow the plate that is cracked to move back together.
- V-groove the current cracks.
- Weld up current cracks. Refer to Illustration 5.
- Reinforcement of the mainframe
- Top frame plates
- Outer frame plates
- Inner frame plates
Preparing the Machine for Service
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Personal injury or death can result from improper lifting or blocking. When a jack is used to lift the machine, stand clear of the area. Use a jack that is rated for the correct capacity to lift the machine. Install blocks or stands before performing any work on the machine. |
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- Put the machine in the servicing position.
- The servicing position is attained by lowering the blade to the ground. If equipped, lower the ripper to the ground.
- Shut off the engine.
- Remove the key which starts the machine.
- In order to make the necessary repairs to the mainframe, remove the cab, platform support, and tracks, as required.
Note: A substantial disassembly may be required in order to complete Step 5.
Inspect Cracks on the Mainframe
- Closely inspect the front portion (A) of the frame for cracks which is shown in Illustrations 1 and 2.
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| Illustration 1 | g01439154 |
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| Illustration 2 | g01439172 |
(A) Cracks | |
- Closely inspect the middle portion of the frame and around the gusset for cracks (B) which is shown in Illustrations 3 and 4.
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| Illustration 3 | g01454519 |
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| Illustration 4 | g01447540 |
Middle portion of frame (B) Cracks | |
Repair Cracks on the Mainframe
Note: While the rework is being done, only repair a single area at a time. This will allow the frame to have adequate material that will support the machine at any given state of the repair process.
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| Illustration 5 | g01447546 |
(C) Plate (D) Plate (E) Plate (F) Plate (G) Plate | |
Note: Important Instructions for Repairing Cracks in Plates
If a crack in the plates is noticed, a proper repair of the crack should include the following steps.
- Grind all the edges in cracked plate (C) in order to make a V-groove which is shown in plate (D) .
- Weld each V-groove in order to achieve 2 to 2.5 mm (0.08 to 0.1 inch) penetration which is shown in plate (E) .
- Grind off any excess weld in order to achieve a flat surface which is shown in plate (F) .
- Weld reinforcement plates onto the original frame plate. Refer to ""Mainframe Reinforcement Process" " in order to strengthen the cracked frame which is shown in plate (G) .
- Only work on one section and one plate at a time in order to maintain structural strength during the repair process.
Reinforce the Mainframe
- Required Parts ( Fabrication of Plates)
- Preparing the Metal for Welding
- Mainframe Reinforcement Process
Required Parts (Fabrication of Plates)
- Cut out cardboard in order to make templates. Refer to the following illustrations.
- Place the cardboard template against the frame in order to make sure that the templates fit.
- Position the cardboard templates onto the steel and trace the outline of the templates onto the steel.
- Cut out the steel plates.
- Weld the steel plates onto the mainframe.
Prior to cutting out the steel plates, use cardboard to make a template for each doubler plates. All dimensions are used only as a reference. Make sure that the template can cover existing cracks. Make any needed adjustments to the dimensions of the plates that are required and then cut the plates for reinforcement.
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| Illustration 6 | g01447127 |
View of cardboard cutout of inner frame plate | |
Note: All plates should have a minimum yield strength of 290 MPa (42061 psi).
Note: A quantity of two plates will need to be fabricated in order to complete the repairs for each side of the frame.
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| Illustration 7 | g01439387 |
The inner frame plate is 6.4 mm (0.25 inch) thick. Modify the geometry of the inner frame plate and shape in order to achieve adequate welding shelf all around. Grind any excess material. (H) 385 mm (15.18 inch) (J) 381 mm (15 inch) (K) 25 mm (1 inch) (L) 167.5 mm (6.6 inch) radius (M) 25 mm (1 inch) | |
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| Illustration 8 | g01439388 |
The corner gusset is 12.7 mm (0.5 inch) thick. (N) 195 mm (7.68 inch) (P) 110 mm (4.33 inch) (R) 15 mm (0.6 inch) (S) 175 mm (6.9 inch) radius (T) 30 mm (1.2 inch) straight leg (U) 15 mm (0.6 inch) | |
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| Illustration 9 | g01439389 |
The top frame plate is 6.4 mm (0.25 inch) thick. (V) 473 mm (18.6 inch) (W) 108 mm (4.25 inch) (X) 50 mm (2 inch) radius (Y) 75 mm (3 inch) | |
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| Illustration 10 | g01439390 |
The outer frame plate is 9.5 mm (0.375 inch) thick. Modify the geometry of the outer frame plate and shape in order to achieve adequate welding shelf all around. Grind any excess material. (Z) 428 mm (16.9 inch) (AA) 295 mm (11.61 inch) (AB) 100 mm (40 inch) (AC) 100 mm (40 inch) diameter (AD) 256 mm (10 inch) (with a 111 degree angle) (AE) 95 mm (3.74 inch) (with a 111 degree angle) (AF) 68 mm (2.7 inch) (AG) 75 mm (3 inch) radius (AH) 75 mm (3 inch) (AJ) 185 mm (7.3 inch) (AK) 100 mm (40 inch) (AL) 50 mm (2 inch) diameter (AM) 25 mm (1 inch) radius (AN) 50 mm (2 inch) diameter (AP) 156 mm (6.14 inch) (AR) 65 mm (2.56 inch) (AS) 25 mm (1 inch) radius (AT) 100 mm (40 inch) diameter (AU) 175 mm (6.89 inch) (AV) 385 mm (15.16 inch) (AW) 18 mm (0.71 inch) (AX) 48 mm (1.89 inch) (AY) 25 mm (1 inch) radius (AZ) 60 mm (2.36 inch) radius (BA) 102 mm (4 inch) (BB) 20 mm (0.79 inch) (BC) 970 mm (38.19 inch) (BD) 350 mm (13.8 inch) (BE) 140 mm (5.5 inch) | |
Preparing the Metal for Welding
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Personal injury can result from flame cutting or welding on painted areas. The effect of gasses from burned paint is a hazard to the person doing the cutting or welding. Do not flame cut or weld on painted areas. |
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Cover all finished bores and threads. Finished bores and threads must be protected from shot blasting, welding and paint spatters.
All grease, water, paint, rust, dirt and scale must be removed before welding. Any of these materials will discharge gas which will cause porosity in the weld deposit. Water and rust will cause hydrogen embrittlement. Hydrogen embrittlement causes cracks in the weld deposit.
Remove any oil or grease that is on the upper frame.
Remove paint, rust, dirt and scale with a wire brush or by buffing or grinding. Shot blasting all work areas can also remove foreign material.
Mainframe Reinforcement Process
Note: Only work on one section and one plate at a time in order to maintain structural strength during the repair process.
- Mainframe reinforcement welding around top frame plate (1) should be fillet welding in order to achieve a 6 mm (0.24 inch) fillet with a 1.5 mm (0.06 inch) penetration.
Note: Stamp the machine serial number on the new left hand side top plate.
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| Illustration 11 | g01457266 |
(1) Top frame plate | |
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| Illustration 12 | g01439771 |
Top view of frame (BH) Welds | |
Note: In area (BH), the existing welds may need to be ground down or the existing welds may need to be gouged out in order to allow the new reinforcement plate to fit closely against the adjacent plate. Be sure to not remove parent plate material.
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| Illustration 13 | g01447789 |
(1) Top frame plate | |
- Mainframe reinforcement welding around outer frame plate (2) and cutouts (BG) should be fillet welding in order to achieve a 8 mm (0.32 inch) fillet with a 1.5 mm (0.06 inch) penetration.
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| Illustration 14 | g01439865 |
(2) Outer frame plate (BF) Scallop (BG) Cutouts | |
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| Illustration 15 | g01439773 |
Outside view of frame (BJ) Welds | |
Note: In area (BJ), the existing welds may need to be ground down or the existing welds may need to be gouged out in order to allow the new reinforcement plate to fit closely against the adjacent plate. Be sure to not remove parent plate material.
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| Illustration 16 | g01447790 |
(2) Outer frame plate (BG) Cutouts | |
- The profile of inner frame plate (3) must fit the adjacent plate that is on the frame within 2 mm (0.08 inch) in order to achieve acceptable weld strength.
Note: Bosses and corner gussets need to be removed and welded to the machine after the rework has been completed.
Note: Repair only one crack at a time.
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| Illustration 17 | g01439864 |
(3) Inner frame plate | |
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| Illustration 18 | g01439775 |
Inside view of frame (BK) Welds | |
Note: In area (BK), the existing welds may need to be ground down or the existing welds may need to be gouged out in order to allow the new reinforcement plate to fit closely against the adjacent plate. Be sure to not remove parent plate material.
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| Illustration 19 | g01447776 |
(3) Inner frame plate | |
- Mainframe reinforcement welding around inner frame plate (3) should be fillet welding in order to achieve a 6 mm (0.24 inch) fillet with a 1.5 mm (0.06 inch) penetration.
- Mainframe reinforcement welding around corner gusset should be (4) 8 mm (0.32 inch) fillet welding in order to achieve a 8 mm (0.24 inch) fillet with a 1.5 mm (0.06 inch) of penetration.
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| Illustration 20 | g01457273 |
(4) Corner gusset | |
Note: The new corner gusset (4) is 25 mm (1 inch) longer than the original corner gusset.
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| Illustration 21 | g01447777 |
(4) Corner gusset | |
Note: Do not start welding and do not stop welding at the corners of gusset (4) .
- Stamp the serial number on the left hand side top frame plate in order to replace the serial number that was covered by the plate.
Contact the Small Track-Type Tractor Product Support Group at BCP in North Carolina for photos from a successfully completed mainframe repair job.